Simple, secure login with multiple authentication providers

CROSS REFERENCE TO RELATED APPLICATIONS

0001This Application is a continuation of U.S. patent application Ser. No. 11/566,648, filed Dec. 4, 2006, now U.S. Pat. No. 7,765,584 which is a continuation of U.S. patent application Ser. No. 10/291,281, now U.S. Pat. No. 7,228,417, filed Nov. 7, 2002, which is a continuation-in-part of U.S. patent application Ser. No. 10/086,104, now U.S. Pat. No. 7,260,836, filed Feb. 26, 2002, all of which are incorporated herein in their entirety by this reference thereto.

TECHNICAL FIELD

0002This invention relates generally to user authentication technology used in an Internet-based distributed network system. More particularly, this invention relates to a system and method for authenticating a user without exposing his password to any participant of a network with multiple-authentication providers.

BACKGROUND OF THE INVENTION

0003The explosive growth of the Internet is changing the ways in which we communicate, conduct business, and pursue entertainment. A few years ago, electronic commerce (E-commerce) was just an interesting concept. By 1999, however, it had become the hottest thing around. Today, not only are consumers buying an enormous volume of goods or services over the Internet, but the business-to-business E-commerce has taken off as well.

0004The basic cell of E-commerce is an electronic transaction, which requires a buyer or user to fill out one or more electronic forms on screen and click a button named “send”, “buy” or “submit”, etc. To complete such an electronic transaction, a user has to go through an authentication process. In other words, the user must provide the seller or service provider with some information such as his or her personal identification, contact information, or even financial information. The authentication process may take from several minutes to hours. Since each seller or service provider maintains its own authentication server and database, millions of seller and service providers might share thousands of millions of consumers or users. Some of the consumers or users might be required to go through the same or similar authentication process again and again if they have transactions with many sellers or service providers. This repetitive authentication not only wastes consumers' precious time, but also burdens the sellers or service providers because they have to expand their databases to keep detailed authentication information for a growing number of users. This situation brings forth a technical need to create a universal, unified single-login infrastructure wherein a specific user may be authenticated once for all and the authentication result is widely recognized by a large number of sellers or service providers.

0005In responding to that need, several approaches have been developed. For example, Microsoft Corporation has introduced a “.NET Passport” single sign-in system. With “.NET Passport”, a user doesn't need to register a member name and password at each new site he or she visits. The user may simply use his or her e-mail address and password that registered as his or her “.NET Passport” to sign in to any participating site or service. The information the user registers with “.NET Passport” is stored online, securely, in the “.NET Passport” database as the user's “.NET Passport profile.” When the user signs in to a “.NET Passport” participating site by typing his or her e-mail address and password in the “.NET Passport” sign-in box, “.NET Passport” confirms that (1) the e-mail address he or she typed is registered with “.NET Passport”, and (2) the password he or she typed is correct. “.NET Passport” then notifies the site that the user has provided valid “sign-in credentials” and he or she is given access to the participating site. Once the user signs in to one “.NET Passport” participating site during an Internet session, he or she can sign in to others simply by clicking the “.NET Passport” sign-in button on each site. Another example is America Online Inc.'s “Screen Name Service” system, which provides free service allowing anyone with a “Screen Name” to easily and securely register at a variety of Web sites. Similar to Microsoft's “.NET Passport” system, the “Screen Name Service” eliminates a user's need to remember multiple names and passwords for all the places he or she visits on the Web. With the “Screen Name Service” system, each user has a “My Profile”, which stores the user's personal information used to make registering at sites across the Web simple and secure. When the user registers at a participating Web site using the service, he or she has the opportunity to choose which fields of information stored by AOL, if any, he or she would like to share with that site. No information will be shared with any Web site without the user's explicit permission. When the user agrees to share certain information with a participating site, that information is conveyed to the Web site at which he or she is registering. Another feature is that the user is provided with a “My Site List”, which is an effective way to manage personal information because it shows the user with which sites he or she has registered with using the service. The user can view the privacy policy of a site to see how it uses information it knows about the user. The user can also decide if he or she would like to be signed into the site without being prompted and if the site should be updated with information if “My Profile” changes.

0006The common characteristic of these approaches is that they implement a centralized solution for authentication and authentication information management.

0007Undoubtedly, the centralized solution may overcome the repetitive authentication and repetitive storage problems that exist in the scattered, disorganized situation. However, the centralized solution has three major disadvantages. First, in a centralized authentication system, because all the login requests go to a central authentication server, the traffic to the server could be very heavy, the requirements for the process capability and database size could be predictably high, and the authentication process would be very slow when the number of requests is overwhelmed for the server. Second, in case the central authentication system fails, all the authentication requests would be suspended. Third, the central authentication service provider could monitor the participating sites' login rates and a site which hosts a user's login page could monitor the user's login information. This situation is surely disliked by most of the participants. Our invention disclosed in the application Ser. No. 10/086,104 filed Feb. 26, 2002 provides a solution to have each authentication carried out at one of participating servers and have the authentication result distributed and cached all over the network of the participating servers so that the authentication results cannot be centrally monitored and even a site which hosts a user's login page cannot monitor a user's login information.

0008The invention provides a solution to guarantee the security of the distributed single-login authentication systems. In a “global single-login user name/password” situation, the user could mistakenly send his password to an unintended recipient that might abuse the information. For example, if the user attempted to type joe@aol.com but mistakenly typed joe@aol.com instead, and when he correctly entered his password and clicked login, the “aol.com” server would receive the user's password. In a “user name/password” situation, the authentication system does not know which authentication server is the correct one. It has to test a number of servers by forwarding each of the tested servers the user name and the password. Therefore, the more servers tested during the process, the more servers know the user's password. If any of the recipients abuses the information, it may cause irreparable harm to the user. This “leaking” of login information is generally unacceptable from a security perspective.

SUMMARY OF INVENTION

0009The invention disclosed herein comprises a system and method of providing secure single-login service with distributed multiple-authentication providers.

0010In the first preferred embodiment, the secure distributed authentication system comprises a client portion and a server portion. The client portion collects a user's regular user name and password and tests that user name and password at a variety of potential authentication servers to check where the login is valid. It combines the password with a time varying salt and a service-specific seed in a message-digesting (MD) hash and generates a first hash value. The client sends the hash value along with the user name and the time-varying salt to a currently selected server. The server portion extracts the user name and looks up an entry under the user name from the authentication server's database. If an entry is found, it retrieves the password and performs a same hash function on the combination of the user name, the service specific seed and the retrieved password to generate a second hash value. Then, it compares two hash values. If these two values match, the user is authenticated. In this way, the system never reveals the password to each tested authentication servers or any accidental recipient that might abuse the information. The authentication process according to the first preferred embodiment includes the following steps <ul id="ul0001" list-style="none"><li id="ul0001-0001" num="0000"><ul id="ul0002" list-style="none"><li id="ul0002-0001" num="0011">(a) the client takes and parses an entered user name and password;</li><li id="ul0002-0002" num="0012">(b) generates a time stamp; iterates a list of authentication servers;</li><li id="ul0002-0003" num="0013">(c) iterates a list of authentication servers;</li><li id="ul0002-0004" num="0014">(d) combines the time stamp, the password and a service specific seed unique to an authentication server selected from the list;</li><li id="ul0002-0005" num="0015">(e) applies a hash algorithm to the combination to generate a first hash value;</li><li id="ul0002-0006" num="0016">(f) finds an IP address for the currently selected authentication server;</li><li id="ul0002-0007" num="0017">(g) sends a data packet to the selected authentication server, wherein the data packet includes the first hash value, the user name and the time stamp;</li><li id="ul0002-0008" num="0018">(h) extracts the first hash value, the user name and the time stamp from the data packet received from the client;</li><li id="ul0002-0009" num="0019">(i) checks whether an entry under the user name is available in the selected authentication server's database;</li><li id="ul0002-0010" num="0020">(j) if no entry under the user name is found, then returns a failure message to the client and repeats steps (b) to (g) for a next selected authentication server;</li><li id="ul0002-0011" num="0021">(k) if an entry under the user name is found, then retrieves the user's password;</li><li id="ul0002-0012" num="0022">(l) combines the time stamp, the retrieved password and the service specificseed unique to the selected authentication server;</li><li id="ul0002-0013" num="0023">(m) applies the hash algorithm to the combination from Step (l) to generate a second hash value;</li><li id="ul0002-0014" num="0024">(n) compares the first hash value and the second hash value;</li><li id="ul0002-0015" num="0025">(o) if these two hash values do not match, then returns a failure message to the client and repeats steps (b) to (g) for a next selected authentication server;</li><li id="ul0002-0016" num="0026">(p) if these two hash values do match, then returns a successful authentication message to the client; and</li><li id="ul0002-0017" num="0027">(q) when the entire list has been tested and no one authenticates the user, then results in authentication failure.</li></ul></li></ul>

0028Note that Steps (a)-(g) are performed in the client software and Steps (h)-(p) are performed at each authentication service (i.e. server side software) before Step (c) iterates to the next authentication service.

0029In the second equally preferred embodiment, the secure distributed authentication system comprises a client portion and a server portion. The client portion collects a user's global user identification (GUID) and password. It combines the password with a time varying salt and a service specific seed in a message digesting (MO) hash and generates a first hash value. The client extracts the regular user name and the domain portion from the GUID. By looking up a local mapping list or a domain name system (DNS), the client obtains an Internet Protocol (IP) address for the authentication server identified by the domain portion. Then, it sends the hash value along with the user name and the time varying salt to the authentication server. The server portion extracts the user name and looks up an entry under the user name from the server's database. If an entry is found, it retrieves the password and performs a same hash function on the combination of the user name, the retrieved password and the service specific seed to generate a second hash value. Then, it compares two hash values. If these two values match, the user is authenticated. In this way, the system does not reveal the password to any accidental recipients. The authentication process according to the second preferred embodiment includes the following steps: <ul id="ul0003" list-style="none"><li id="ul0003-0001" num="0000"><ul id="ul0004" list-style="none"><li id="ul0004-0001" num="0030">(a) The client parses an entered GUID and password;</li><li id="ul0004-0002" num="0031">(b) generates a time stamp;</li><li id="ul0004-0003" num="0032">(c) extracts the user name from the GUID;</li><li id="ul0004-0004" num="0033">(d) extracts the domain portion from the GUID;</li><li id="ul0004-0005" num="0034">(e) combines the password and a service specific seed unique to the target authentication server identified by the domain portion and hash the combination by mapplying a hash algorithm;</li><li id="ul0004-0006" num="0035">(f) combines the result of (e) with the time stamp to generate a first hash value;</li><li id="ul0004-0007" num="0036">(g) appends a unique domain name to the domain portion to form a fully qualified domain name (FQDN) for the target authentication server;</li><li id="ul0004-0008" num="0037">(h) looks up the FQDN from a local mapping list to obtain an IP address representing the target authentication server;</li><li id="ul0004-0009" num="0038">(i) if Step (h) fails, looks up the FQDN in a domain name system (DNS) to obtain an IP address representing the target authentication server;</li><li id="ul0004-0010" num="0039">(j) sends a data packet to the target authentication server, wherein the data packet includes the first hash value, the user name and the time stamp;</li><li id="ul0004-0011" num="0040">(k) extracts the first hash value, the user name and the time stamp from the data packet received from the client;</li><li id="ul0004-0012" num="0041">(l) checks whether an entry under the user name is available in the target authentication server's database;</li><li id="ul0004-0013" num="0042">(m) if no entry under the user name is found, then returns a failure message to the client;</li><li id="ul0004-0014" num="0043">(n) if an entry under the user name is found, then retrieves the user's password;</li><li id="ul0004-0015" num="0044">(o) combines the time stamp, the retrieved password and the service specific seed unique to the target authentication server;</li><li id="ul0004-0016" num="0045">(p) applies the hash algorithm to the combination from Step (<b>0</b>) to generate a second hash value;</li><li id="ul0004-0017" num="0046">(q) compares the first hash value and the second hash value;</li><li id="ul0004-0018" num="0047">(r) if these two hash values do not match, then returns a failure message to the client; and</li><li id="ul0004-0019" num="0048">(s) if the these two hash values do match, then returns a successful authentication message to the client.</li></ul></li></ul>

0049The process may further include a step to automatically map an unrecognized FQDN to a default server for authentication.

BRIEF DESCRIPTION OF THE DRAWINGS

0050<figref idref="DRAWINGS">FIG. 1</figref> is a block diagram illustrating an exemplary network that facilitates a distributed authentication service according to the invention;

0051<figref idref="DRAWINGS">FIG. 2</figref> is a schematic diagram illustrating a simplified network including a client and an authentication server;

0052<figref idref="DRAWINGS">FIG. 3</figref> is a flow chart illustrating an exemplary authentication process performed by the client portion according to the invention;

0053<figref idref="DRAWINGS">FIG. 4</figref> is schematic diagram illustrating an exemplary domain name system, from which a client may obtain the IP address of an authentication server in case it fails to obtain the IP address from a local mapping list;

0054<figref idref="DRAWINGS">FIG. 5</figref> is a table diagram illustrating an IP address database associated with the domain name server in the network; and

0055<figref idref="DRAWINGS">FIG. 6</figref> is a flow chart illustrating an exemplary authentication process performed in the server portion according to the invention.

DETAILED DESCRIPTION

0056<figref idref="DRAWINGS">FIG. 1</figref> is a block diagram illustrating an exemplary network <b>100</b>, which provides distributed authentication service among a global authentication federation. The MCN network includes at least one client, e.g. client <b>101</b>, and a number of authentication servers, e.g. servers <b>111</b>-<b>113</b>, which are communicatively connected via the Internet <b>105</b>.

0057Each client may include a browser <b>103</b> which displays an HTML file. The HTML facilitates a number of functions, which are typically implemented in JavaScript. Alternatively, the client may be implemented as a standalone application for managing the authentication process.

0058Each authentication server represents a participant of the global authentication federation and has an associated database, e.g. DB <b>01</b>-DB <b>03</b>, which caches its registered users' information and any authentication token from other participating authentication servers. The clients and the authentication servers can access a local domain name server, which is one of many domain name servers coupled in a domain name system (DNS).

0059The distributed authentication system embodied in the MCN network <b>100</b> according to the invention includes a client portion, which runs on a client device, and a server portion, which runs on a participating server of the global authentication federation.

0060<figref idref="DRAWINGS">FIG. 2</figref> is a schematic diagram illustrating a simplified MCN network including a client <b>101</b> and an authentication server <b>111</b>. Typically, the client <b>101</b> includes (1) a user interface <b>121</b><i>a</i>, which enables a user to login by entering his user ID and password; (2) a central control piece <b>122</b><i>a</i>, which implements client logic controlling the authentication process complying with the client portion of the authentication system; and (3) a message digest algorithm computing engine <b>123</b><i>a</i>, which performs a oneway hash function.

0061The authentication server <b>111</b> includes (1) an input/output <b>121</b><i>b</i>, which is used to receive requests and send back replies; (2) a controller <b>122</b><i>b</i>, which implements the server's logic controlling the authentication process complying with the server portion of the authentication system; and (3) a message digest algorithm computing engine <b>123</b><i>b</i>, which performs the same one-way hash function as that performed in the client portion. In addition, the server <b>111</b> is communicatively coupled to a database DB <b>01</b>, which maintains its registered users' detail information including their passwords.

0062The hash function performed by the hash engines <b>123</b><i>a </i>and <b>123</b><i>b </i>is a mathematical function that maps values from a larger domain into a smaller range; in particular, they apply such a function to a password combined with certain seeds such as a time-specific seed or/and service-specific seed. The hash process is a one-way process, in which the hash engine applies a cryptographically secure hash algorithm to a combination of various parameters and generates a hash value. It is almost impossible to reverse the process and deduce the password.

0063The hash engines <b>123</b><i>a </i>and <b>123</b><i>b </i>may take advantage of an operation known as message digesting (MD). An MD algorithm takes as input a message of arbitrary length and produces as output a 128-bit fingerprint or message digest of the input. It is computationally infeasible to produce two messages having the same message digest, or to produce any message having a given pre-specified target message digest. There are a number of message digesting algorithms available for use, some of which are provided by Rivest, Shamir and Associates (RSA). RSA message digesting algorithms have different versions such as MD2, MD4 and MD5. Other algorithms, such as Secure Hash Algorithm (SHA) which is a NIST standard, are also available in the marketplace.

0064The MD5 algorithm is usually used in digital signature application, where a large file must be compressed in a secure manner before being encrypted with a secret key under a public crypto-system such as RSA. For details about MD5 algorithm, see R. Rivest, <i>The MD</i>5 <i>Message-Digest Algorithm</i>, RFC 1321, MIT Laboratory for Computer Science and RSA Data Security, Inc.

0065Although an MD5 or its equivalent is preferably used in the embodiments described below, MD2 and MD4 digesting algorithm or other functionally equivalent algorithms can also be used in the scheme of the invention.

0000Process Performed by the Client Portion

0066In one preferred embodiment, the client portion of the authentication system takes the user's regular user name and password and maintain a mapping list of the fully qualified domain names (FQDN) for all MCN participants and their Internet Protocol (IP) addresses.

0067<figref idref="DRAWINGS">FIG. 3</figref> is a flow chart illustrating an exemplary authentication process <b>300</b> performed by the client portion according to the invention. The process includes the steps of: <ul id="ul0005" list-style="none"><li id="ul0005-0001" num="0000"><ul id="ul0006" list-style="none"><li id="ul0006-0001" num="0068">Step <b>301</b>. The client <b>101</b> takes and parses the user name and password entered by a user in the login page.</li><li id="ul0006-0002" num="0069">Step <b>302</b>. Generates a time varying salt such as a time stamp.</li><li id="ul0006-0003" num="0070">Step <b>303</b>. Iterates a list of authentication servers from 1 to n to select the right authentication server.</li><li id="ul0006-0004" num="0071">Step <b>304</b>. Combines the user's password with a service-specific seed unique to a currently selected authentication server to construct a “keyed one-way hash” of the password by applying a message-digesting algorithm.</li><li id="ul0006-0005" num="0072">Step <b>305</b>. Combines the “keyed one-way hash” with the time stamp to compute a more secure hash value (the first hash value).</li></ul></li></ul>

0073Note that the combination of the password with the service-specific seed makes it impossible to deduce what hash would be passed as authentication to other services. Furthermore, the combination of the time stamp and the “keyed one-way hash” makes the hash value (message digest) dynamic. In other words, the hash value is only valid for this current session. When the user logs on at a different time, the hash value will be different. <ul id="ul0007" list-style="none"><li id="ul0007-0001" num="0000"><ul id="ul0008" list-style="none"><li id="ul0008-0001" num="0074">Step <b>306</b>. Sends the user name, the time stamp and the hash value to the currently selected authentication server using one or more data packets as carrier.</li><li id="ul0008-0002" num="0075">Step <b>307</b>. Receives a result of authentication from the authentication server. If the authentication is successful, proceeds to Step <b>308</b>. If it is unsuccessful, proceeds to Step <b>309</b>.</li><li id="ul0008-0003" num="0076">Step <b>308</b>. Returns a successful authentication result to the client.</li><li id="ul0008-0004" num="0077">Step <b>309</b>. Checks if there is an untested server in the list. If yes, then repeats steps <b>302</b>-<b>306</b> for a next authentication server selected from the remaining servers in the list.</li><li id="ul0008-0005" num="0078">Step <b>310</b>. If no, returns an authentication failure message to the client. <br /> In a situation where the client portion of the authentication system keeps an updated list of MCN participants but fails to keep updated IP addresses for each participant, the client <b>101</b> may start a Domain Name System (DNS) lookup process to obtain the IP address of the currently selected authentication server. <figref idref="DRAWINGS">FIG. 4</figref> illustrates an exemplary domain name system <b>200</b> incorporated in a global network. A domain name system (DNS) is a general-purpose, replicated, distributed data query service for looking up host Internet Protocol (IP) addresses based on host names. It is hierarchical, consisting of domains, sub-domains, sites, and hosts. Unique names are formed from smallest to largest, and are of the form “user@host.site.subdomain.domain”, where host and site are often optional. </li></ul></li></ul>

0079On the Internet, domain names typically end with a suffix denoting the type of site. For example, “.COM” for commercial sites and “.ORG” for organizations. A name resolution client, such as the client <b>101</b> in <figref idref="DRAWINGS">FIG. 1</figref> and <figref idref="DRAWINGS">FIG. 2</figref>, can be configured to search for host information in the following order: first in the local/etc/hosts file, second in network information service (NIS), and third in DNS. This sequencing of naming services is sometimes called name service switching. DNS can be queried interactively using command nslookup.

0080The MCN network <b>100</b> illustrated in <figref idref="DRAWINGS">FIG. 1</figref> is registered under a unique domain name, for example MCN.ORG, in the central location of the DNS <b>200</b>. The MCN network <b>100</b> requires each participant to register its authentication server as an individual machine under the MCN domain. In other words, the host names of the authentication servers share a common suffix. For example, AOL, as a participant host, registers its authentication server as AOL.COM.MCN.ORG under the unique domain MCN.ORG. The domain name server DNS <b>06</b> associated with the MCN network <b>100</b> just treats each participant authentication server as a host machine. For example, it treats AOL.COM.MCN.ORG as the host name of AOL Authentication Server <b>101</b>.

0081<figref idref="DRAWINGS">FIG.5</figref> illustrates a database DB <b>16</b> associated with the domain name server DNS <b>06</b>. The database maintains a list of fully qualified domain names (FQDN) for the registered authentication servers. A FQDN consists of its local hostname and its domain name, including a top-level domain. For example, AOL.COM.MCN.ORG is a FQDN, in which AOL.COM is a host name, MCN.ORG is a domain name, and .COM is a top-level domain name. Each of FQDN has a unique IP address, which was installed in the database DB <b>06</b> when a commercial participant of the federation registered its authentication server under the domain MCN.ORG.

0082When the IP address for the currently selected authentication server <b>111</b> is returned, the client <b>101</b> sends the secure hash value along with the user name and the time stamp to the currently selected authentication server <b>111</b>. If the currently-selected authentication server cannot authenticate the user, then the controller selects another candidate authentication server in the list and repeats the process as described above until the correct authentication server authenticates the user or all authentication servers fail to authenticate the user.

0083In an equally preferred embodiment, a user is required to input his global user identification (GUID) and password for authentication. A GUID is in a universal name space format, for example, an email address format. Hence any given GUID consists of two portions separated by a delimitation symbol, such as @. The first portion is the user's user name, and the second portion is a domain name indicating the domain of a server, such as AOL.COM, with which the user registered. For example, an AOL-registered user with a user name “joe” should enter his GUID joe@AOL.COM and his password secret911 for authentication by AOL Authentication Server <b>111</b>, which is registered as AOL.COM.MCN.ORG under the domain MCN.ORG.

0084Referring back to <figref idref="DRAWINGS">FIG. 4</figref>, assuming the user enters his GUID and password from a page <b>201</b> hosted by ZYX.COM. Once the user gets logged in, the client portion of the authentication system parses the user's GUID joe@AOL.COM and extracts the domain portion AOL.COM from the GUID. Then, it appends the MCN domain name as a suffix to the domain portion. As a result, a FQDN AOL.eOM.MCN.ORG is formed.

0085The client portion of the authentication system first looks up a local domain name server DNS <b>05</b> to find location of the authentication server with a FQDN AGL.COM.MCN.ORG. After if fails in DNS <b>05</b>, it populates the lookup request to its upper level DNS <b>02</b>. After it fails in DNS <b>02</b>, it populates the lookup request to the top DNS <b>01</b>, where it locates the DNS <b>03</b> for the “.ORG” network. It further locates the DNS <b>06</b> for the MCN network <b>100</b> and eventually locates AOL.COM.MCN.ORG. In responding to the lookup request, the DNS returns a unique IP address for AOL.COM.MCN.ORG to the client <b>101</b>. This unique IP address is automatically cached in the DNS along the returning route, i.e., DNS <b>06</b> -7DNS <b>03</b> -7DNS <b>01</b> DNS <b>5</b><b>02</b> -7DNS <b>05</b>. Note that the critical point is that the DNS lookup is distributed and cached, and as a result, the DNS lookups cannot be centrally-monitored by any participant of the federation.

0086The distributed authentication system embodied in the MCN network <b>100</b> may include a default server <b>114</b> with a FQDN DEFAULT.MCN.ORG. If the DNS lookup totally fails, i.e. the domain included in the lookup request sent by the client device <b>101</b> is not recognized by the DNS <b>200</b>, a DNS resolver in the central location of the DNS <b>200</b> can automatically map the unrecognized domain to the def.ault server <b>114</b>. The default server <b>114</b> takes responsibility to authenticate the user by performing a hash process as described below (Process Performed By The Server Portion). The end result is that all possible MCN <b>10</b>'s are automatically distributed to the appropriate servers.

0087In another situation, all participants are not registered in a specific domain.

0088Instead, each participating authentication server is registered with a standard server name in its main server's domain. For example, AOL Authentication Server <b>111</b> has a FQDN AUTH.AOL.COM, USPTO's authentication server has a FQDN AUTH.USPTO.GOV, etc. In other words, the host names of these authentication servers share a common prefix but they reside in different domains. When the user gets logged in, the authentication system first parses and extracts the domain portion of the GUID. Then, it either checks a local mapping list or looks up the DNS <b>200</b> or performs both local list checkup and DNS lookup to locate the IP address for the target authentication server. If the IP address for the target authentication server is not found, the system may map the authentication request to the default server <b>114</b> as described above.

0089The DNS lookup process and the hash process can be performed sequentially or simultaneously. As soon as both the IP address and the hash value are available, the client sends the time stamp, the user's user name, and the hash value to the authentication server <b>111</b> for authentication. In the second preferred embodiment, because the authentication server is clearly identified by the GUID entered by the user, the authentication system does not need to iterate a list of authentication servers to find the correct one. It is slightly inconvenient for the user to type in his GUID, but the authentication process is much faster. In practice, the schemes in the first preferred embodiment and the second preferred embodiment can be combined. In other words, the authentication system can take either a regular user name such as “joe” or a GUID such as “joe@aol.com”.

0000Process Performed by the Server Portion

0090When the authentication server <b>111</b> receives the authentication request from the client <b>101</b> in its I/O block <b>121</b><i>b</i>, it passes the request to the controller <b>122</b><i>a</i>. The controller <b>122</b><i>a </i>extracts the hash value, the user name and the time stamp from the received data packet or packets, and looks up the server's database DB <b>01</b> to check whether there is an entry for the user. If it finds an entry for the user, it retrieves the user's password stored in the database DB <b>01</b>. Then, the controller combines the time stamp with the server's service seed and the retrieved password in the same specific logic order used in the client portion. It then passes the combination to the message digest computing engine <b>123</b><i>b</i>, which applies the same algorithm as used in the message-digest computing engine <b>123</b><i>a</i>, to the combination to generate a hash value. The controller <b>122</b><i>b </i>compares the resulted hash value with the received hash value from the client <b>101</b>. If two hash values match, then the authentication is successful; otherwise, the server returns a failure message to the client.

0091Once the user is successfully authenticated, the authentication server returns an authentication token to the client and distributes the authentication result to other participating servers of the federation. The authentication token is cached in the client device. When the user sends request to any other participant servers, the authentication token is automatically attached. The attached authentication token is recognized by any participating server of the federation and is automatically cached in the participating server's database when the participating server receives the authentication token. In this way, the user's detailed authentication information is stored only in one participant server's authentication database, but the authentication token is distributed all over the participants' authentication databases. Because an authentication server does not need to store every user's detailed authentication information, its authentication database can be relatively small in size.

0092<figref idref="DRAWINGS">FIG. 6</figref> is a flow chart illustrating an exemplary authentication process <b>400</b> performed in the server portion according to the invention. The process includes the steps of: <ul id="ul0009" list-style="none"><li id="ul0009-0001" num="0000"><ul id="ul0010" list-style="none"><li id="ul0010-0001" num="0093">Step <b>401</b>. The authentication server receives an authentication request carried by one or more data packets from the client. The authentication request includes the user name, the time stamp and the hash value.</li><li id="ul0010-0002" num="0094">Step <b>402</b>. Extracts the hash value, the user name and the time stamp from the data packet or packets.</li><li id="ul0010-0003" num="0095">Step <b>403</b>. Looks up its database to find an entry based on the user name. If the server finds an entry for the user, proceeds to Step <b>405</b>; otherwise the system proceeds to step <b>404</b>.</li><li id="ul0010-0004" num="0096">Step <b>404</b>. Returns an authentication failure message to the client and the authentication process continues on the client portion.</li><li id="ul0010-0005" num="0097">Step <b>405</b>. If the server finds an entry for the user, retrieves the user's password from the database.</li><li id="ul0010-0006" num="0098">Step <b>406</b>. Combines the user name, the password and the server's service seed.</li><li id="ul0010-0007" num="0099">Step <b>407</b>. Applies the hash algorithm to the combination.</li><li id="ul0010-0008" num="0100">Step <b>408</b>. Compare the hash value from Step <b>407</b> (the second hash value) with the hash value received from the client (the first hash value). If two hash values don't match, proceeds to Step <b>404</b>.</li><li id="ul0010-0009" num="0101">Step <b>409</b>. If two hash values do match, returns a successful authentication message to the client.</li></ul></li></ul>

0102Although the invention is described herein with reference to the preferred embodiment, one skilled in the art will readily appreciate that other applications may be substituted for those set forth herein without departing from the spirit and scope of the present invention.

0103Accordingly, the invention should only be limited by the Claims included below.